This invention relates to the operation of remote medical navigation systems, and in particular to the operation of such systems using ultrasound imaging, preferably with reduced reliance on x-ray imaging.
Remote navigation systems have been developed that permit the distal end of a medical device disposed in a subject's body to be remotely controlled so that the device can be navigated through the body, for example through a subject's vasculature. Such systems include magnetic navigation systems which use one or more external source magnets (either permanent magnets of electromagnets) to create a magnetic field in a direction that causes magnetically responsive elements on the medical device to align in a desired direction. Such systems also include mechanical systems which use push wires and pull wires, or gears, or other elements to orient a medical device directly or to orient a guide that orients the medical device.
While remote medical navigation systems are making navigation of medical devices through the body faster and easier and are finding an increasing number of applications, physicians are accustomed to watching the procedure on fluoroscopic images in order to control the medical device. This can result in significant exposures to subjects and even greater exposures to physicians and healthcare practitioners who might participate in several procedures per day.
Another significant advantage of some of the embodiments of the present invention derives from removing live fluoroscopy in favor of ultrasound guidance during a magnetic navigation, which allows the field source magnets to be much closer to the subject, since ultrasound equipment is smaller and space for x-ray equipment and beams need not be interfered with. The much closer navigation source magnets can be drastically reduced in size and cost. In addition, suite and equipment shielding will be greatly reduced in complexity and expense, as will floor support needed for the large source magnets such as the Niobe magnet (available from Stereotaxis, Inc., St. Louis, Mo.). Even when fluoroscopy is used in an aiding fashion, it can be removed during the magnetic navigation to retain some or all of these advantages.